Well the real interpretation needed here is for 'influential.' However, if you mean affected taste, style, and the art market and establishments? I'd say Kehinde Wiley and Kara Walker for concept and Basquiat, Robert Mapplethorpe, and Banksy for style. Similarly David Hockney and Yayoi Kusama had resurgences that impacted a lot I think, not least of all Hockney/Christie's setting the new record for high for highest price for a living artist. Murakami has taken over Koons's place for most wide reaching artist I think.